


Killing Cahill

by Caitriona_3, GalahadsGurl, GrimmLegacy (GalahadsGurl), PackGirl (Caitriona_3)



Series: Complicated: The Epic Grimm Family Saga [34]
Category: Marvel Cinematic Universe, Mission: Impossible (Movies), Nikita (TV 2010), Rogue One: A Star Wars Story (2016)
Genre: Alternate Universe, Alternate Universe - Canon Divergence, Crossovers & Fandom Fusions, Jeremy Renner Character Combinations, Multi, Multiple Crossovers
Language: English
Status: Completed
Published: 2020-07-18
Updated: 2020-07-21
Packaged: 2021-03-05 02:48:52
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 3,590
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25367119
Author URL: https://archiveofourown.org/users/Caitriona_3/pseuds/Caitriona_3, https://archiveofourown.org/users/GalahadsGurl/pseuds/GalahadsGurl, https://archiveofourown.org/users/GalahadsGurl/pseuds/GrimmLegacy, https://archiveofourown.org/users/Caitriona_3/pseuds/PackGirl
Summary: The time has come to deal with one of the family nightmares.
Relationships: Marina Petrovka & Owen Elliot, William Brandt & Owen Elliot, William Brandt/Marina Petrovka
Series: Complicated: The Epic Grimm Family Saga [34]
Series URL: https://archiveofourown.org/series/1489391
Comments: 71
Kudos: 46





	1. Killing Cahill Cover Art

**Author's Note:**

> Hello all! We're back - and while this first week might be a bit slow, we've got all kinds of plans for you. Hope you enjoy!
> 
> Set in October 2005.

[ ](https://imgur.com/1H4a3DC)

_“What we call emancipation is always and of necessity simply the free choice of the soul between one set of limitations and another.”_   
_~G.K. Chesterton_


	2. Killing Cahill

**Notes for the Chapter:**

> Hello all! We're so excited to be back. Our vacation was wonderful, and we worked on so much stuff for all of you! We can't wait to hear what you think! Each and every one of you is amazing and wonderful and awesome. Your comments and kudos definitely make our days, and we're so grateful you've continued to stick with us for so long. 
> 
> Translations at the end, per usual. Enjoy and we can't wait to hear what you think!

KILLING CAHILL

Marina looked up from the pot she stirred as the kitchen door opened. A smile began to curve her lips as she spotted Owen standing in the opening. “Welcome home,” she began, only to let her words fall away as she spotted the dark light in his eyes. 

“Hey, Boss Lady,” he greeted. “You know where the Boss is?”

“In his office,” she replied, her smile fading into a frown. “Are you okay?”

“Yeah.” A flashfire grin slipped across his hard mouth. “Might want to put dinner on simmer though. I have news.”

News. 

Owen only had one job over the past few weeks – and they all had a vested interest in his hunt. The _Gadyuka_ scratched at her bonds, wanting to be let loose to join the hunt. Turning back to the stove, Marina began doing as he recommended. “Why don’t you go get Misha out of his office?” she suggested. “I’ll get things handled in here and meet you both in the library.”

“Can do.” 

When she didn’t hear his footsteps retreating, she glanced over her shoulder to find his thoughtful eyes resting on her. “Lucky?”

“Is anyone else home?”

“Cassian’s in his room,” she confirmed. “Doing his homework.” Giving a soft hum as her mind caught up with his concerns, she nodded at him. “I’m assuming I should have him head to Doyle’s for a few hours?”

“Probably a good idea,” he agreed.

While her friend disappeared, Marina finished settling dinner and took off her apron, draping it over one of the chairs in the small nook. Heading up stairs, she turned towards her son’s room where she paused in the open doorway to take a moment to watch him. Bent over his books and hard at work, Cassian didn’t spot her. So she tapped her knuckles on the doorframe. “Knock, knock.”

“ _Hola, Mamacita_.” A warm smile spread over Cassian’s face as he stood up to face her. She moved forward to give him a warm hug. He accepted but pulled back to frown down at her. “Everything okay?”

Refusing to lie to her son, Marina side-stepped the question. “Can I ask you a favor?”

“Of course,” he agreed immediately. “What’s wrong?”

“The kind of classified you can’t overhear, _vorishka_.”

He needed no further explanation. “I can head over to Tammy’s,” he nodded, turning away to pack his stuff into his backpack. “And I’ll take my phone. Just call me when it’s okay to come back home.”

“Thank you, love,” she smiled, one hand coming to rest on his arm. “I’m sorry to interrupt, but-.”

“ _Mamacita_ , it’s all right.” Cassian pulled his backpack onto one shoulder. “You and Papa told me when I first got here that things like this might happen.” Leaning forward to press a warm kiss to her cheek, he winked. “Sometimes that’s the job.”

“Indeed.” Marina gave a warm chuckle. “So, for dinner tomorrow, what do you think about _ropa vieja_ , with _fricasé de pollo_ and maybe even a _flan_ for dessert?"

“Sounds awesome,” he agreed with a bright smile. “I’ll see you later.”

“We’ll call you.” 

After accepting one more hug, she followed him downstairs. Cassian headed out the front, door slamming behind him. She walked into the library, shaking her head at her son’s typical exuberance. Will and Owen stood at her desk, leaning over a map and some blueprints. Given the expressions on the men’s faces, she expected not to like the revelations of the upcoming talk. Owen’s stoic expression held an edge of temper that bespoke of coming bodies while Will’s close-cropped hair looked as if he’d been running his hands through it multiple times in the few minutes she’d been dealing with their son.

Even as she watched, he lifted a hand to scrub through the blond strands as he cursed under his breath.

“Cassian just left,” she announced to the room, letting them know of her arrival. She joined them at the table in time to capture her partner’s hand as he yanked on the curve of his ear, a nervous tick he rarely displayed. “Stop that,” she ordered. “You’re going to hurt yourself.”

He muttered something under his breath but kept his glare on the blueprints.

She glanced over at Owen. “What did you find out, Lucky?”

“Welcome to Sterisyn Morlanta, Boss Lady,” he replied, waving a hand over the spread of paperwork.

“Sterisyn Morlanta?” she echoed. “I don’t understand?”

“It’s a federal think tank,” Will grumbled. “And the current employer of one Doctor Frank Cahill.”

“And it’s in Bethesda,” Owen added, his lips twisting in a scowl.

“You’re saying Cahill is in **Maryland**?” she demanded. “Less than three hours away by car?”

“Living in a big house,” he nodded. “Probably swimming in money.” His jaw tightened as wrath flashed in his light eyes. “Who knew being a slimy bastard could be so lucrative?”

“Ross.” 

Both of them turned to Will at the icy bite of his tone. “Ross?” Owen repeated.

“He got his promotion to General because of Cahill.” Mercurial eyes glanced up for a brief moment before returning to stare at the papers spread across the desk. “It doesn’t surprise me that Cahill benefited from it as well.”

Marina frowned at the reminder. “What did Dave and Nick say?”

“Both of them are in our corner,” he replied. “They’ll back any play we make.” For a moment, the hard lines softened as an amused light lit his face. “However, Dave and Denise are – and I quote – ‘reminding Zach he’s American’. Dave has no idea of what we’re doing and would like us to keep it that way.”

For a moment, she pushed the darkness of the topic away as she let herself giggle. “The joys of plausible deniability.”

“Indeed.” Then the light fell away and Will’s face hardened again. “Do we know what Sterisyn Morlanta does?”

“The security in this place is obscene,” Owen replied, eyes darkening. “Whatever they’re doing in there, they don’t want anyone to know about it.”

Her smile dying, Marina huffed out a breath. “So how do we take out Cahill?”

“There are ways to get in,” he reminded her. “Stealing a badge, impersonating a tech . . . just to name a few. Even the most guarded place has cracks people can slip through.” He shook his head. “Finding out what he’s doing there, though, that would be harder. Sure, I know where his office is, but that’s not my main concern.”

“How do we destroy what he’s working on?” Will asked.

“Ding, ding, ding.” Owen pointed at him. “We have a winner.”

“Can we find out where his labs are?” Marina asked. “Anything he’s working on would be there.”

“Sure, I can find out,” he agreed, shoulders moving in a half-hearted shrug. “That doesn’t tell us how to destroy it.”

“An electrical short might work.”

Will lifted his eyebrows. “A short?”

“Jason knows how to stage one,” she explained. “We’ve had him do it on a mission before.”

“Jason can’t go,” he began.

“Of course, he can’t,” she interrupted. “But if he can pass on how to set it up . . .”

“I can do it,” Owen finished.

“So Lucky causes the fire while I handle Cahill in his office,” she nodded. “Two birds, one stone.”

A frown creased Will’s brow as he turned his eyes towards the blueprints once more. “What about the rest of the employees?”

“Are we sure they’re innocent?” Marina wondered. “This is **Cahill**.”

“It’s also a government think tank,” he pointed out. “They employ all kinds of people. Can you live with the destruction? If we don’t know for sure, guilt or innocence?”

She flinched at the idea. All of them knew the answer to his question – no, that kind of weight would sit too heavy on her shoulders. On the other hand, they did have other things to worry about. “Salt the ground, remember?” she asked, turning back to the blueprints. “We can’t risk Betty.”

“There’s something else to consider.” Owen pulled a picture out of the stack of papers. “This is his house – his very nice, very lovely home . . . that has an extra room which isn’t on the plans. Not that the science makes any sense to me, but he’s definitely working in that room. Even I know what genetic codes look like when written out.”

“How do you know that?”

“Because I’ve been inside.” He cocked an eyebrow at her. “He’s paranoid, but his security isn’t nearly as stringent as it is at Sterisyn Morlanta. This would probably be the best way to get to him.”

“And his work at this ‘think tank’?” Marina prompted, eyebrows up in curious concern.

“I don’t like not knowing,” Will agreed, though he shook his head, “but anything he’s working on there will be under stringent review by the government. He won’t have anything about Betty there. Too much oversight. And if word reaches Ross about Cahill playing around with DNA – especially **Betty’s** DNA?”

“Goodbye, Cahill.” Marina nodded. She agreed with Betty’s analysis – Ross wanted complete dominion over Betty’s genius and would destroy Cahill for touching her. A small smirk curled her mouth as she imagined the impotent frustration he must be feeling now that he’d lost all of his control since the incident at Culver.

Couldn’t have happened to a nicer asshole.

“What’s the play?”

Owen smirked and Marina lips curved into a smug smile of her own. They both understood the tacit acceptance in Will’s question. She watched as the younger man straightened up and reached over to pull out a second set of blueprints. “Cahill lives alone,” he replied. “His children live independently, and he’s estranged from his wife.”

“Or her from him,” she muttered.

“Could be,” he agreed. “Either way, she doesn’t live there. So there’ll be nothing to stop us from torching the place and watching it burn.” Something cynical sharpened his smirk. “Since they’re not divorced yet, we might even be doing his wife a favor – she’s still the beneficiary on the house and the life insurance policy.”

“I don’t care about the wife,” Will noted. “I never met her, so as far as I’m concerned, she’s innocent.”

“Good to know.” The smirk shifted into a full grin. “Cahill’s loss would be good for her – in more ways than one, the bastard.”

The manic grin on her friend’s face earned a little flutter deep in Marina’s gut, causing a frown to flicker over her mouth before she resolved to ignore it. Instead, she reached up to pull him down so she could press a quick kiss to his cheek. “You’re crazy.”

“No crazier than you, Boss Lady,” he shot back with a wink.

With nothing she could say in argument, Marina turned again to the blueprints. “Are we still thinking an electrical short would be the best idea?”

“Makes the most sense,” Owen agreed. “The house is maintained, but it’s old. Something small in an attic, somewhere out of the way where it wouldn’t be immediately noticed?” He shrugged. “Shouldn’t raise too many questions.”

Will nodded, turning so he rested one hip on the edge of the desk. “Neighbors?”

“None nearby,” he confirmed. “He sees his son on the weekends, but if we plan his execution on a Monday, it should be a couple of days before someone misses him.”

“What about Sterisyn? Won’t they miss him?”

“He doesn’t go in every day,” Owen replied. “From what I’ve seen, his schedule is set by his own whims. It doesn’t look like they’ll have any reason to find his absence strange.”

“All right then.” Will rose to his full height and gave them both a solemn nod. “Make it happen.”

Three days later, Marina felt as though she might come out of her skin.

While she understood the need to remain cooped up in this hotel room until Owen confirmed the final details on their plan to deal with Cahill, that knowledge did nothing to calm the _Gadyuka_ raging in the back of her mind. The Viper longed for chaos and bloodshed . . . and she wanted it **now**. To be fair, Marina had kept the Red Room’s creation locked up for years.

Long past time to open the cage for a bit.

When the door opened, sunlight spilled into the room for a brief moment before Owen blocked it as he stepped through the open space. “You okay, Lady Viper?”

Warmth pooled through her as she beamed at the new variation of her nickname. Not for the name itself, but for the man who gave it to her. The feeling had become increasingly familiar over the past few months and she rose to let him wrap his arms around her shoulders. He hated leaving her alone at the hotel – and she didn’t like it much either. So the hug comforted them both, even to the point of soothing the Viper’s rage.

It took a moment, but at last she managed to sigh out a relaxing breath. “As well as I can be,” she agreed. “You?”

“I’m all right.” She felt him press a kiss to the crown of her head before he released her and stepped back. “I’ll be happier when this is done and we can go home.”

“I’m on the same page.” Reluctant, but resolute, she took her own step back. “What did you find?”

“He’s home . . . and there’s no sign of him having plans to leave any time soon.”

“Tonight, then?”

“After the sun goes down.” Owen folded his arms over his chest. “No reason to give him any warning.”

Marina’s fingers curled into fists as her jaw hardened. A few short hours and Cahill would be dead . . . then maybe her Misha could sleep a little better. “I’m ready whenever you are,” she promised.

“I know,” he chuckled. “You’ve been raring to go for days.”

“Do you blame me?”

Cornflower blue eyes turned cold as his own rage boiled up. “Not a chance in hell.”

Sundown took forever. Marina passed the time sharpening her favorite knife over and over again, her eyes focused on a point just past the blade as she let the sound help her meditate. She could feel the weight of Owen’s gaze, but he seemed content to let her alone. The meditative state kept thoughts from swirling around her mind until she felt a gentle touch on her shoulder. Looking up, she locked eyes with a focused cornflower blue. “That time at last?”

“Long past, don’t you think?”

“Assuredly.” Marina slipped her whetstone into its case before shoving her knife into the holster at her thigh. “Are we ready?”

“Everything’s with the bike,” he replied. “As soon as the job’s done, we can head home.”

Searching the room, she looked for anything that might give them away. She pulled on gloves and accepted the wipes from Owen to help him clear away all marks of their stay. “I’ll take the left side of the room and the bathroom if you’ll take the right side and the doors.”

“Deal.”

Clean up took a little time, but they preferred to be thorough. Once finished, they wiped down the outside look and doorknob as they exited the room before stripping off their gloves. They shoved them in a bag to be disposed of later. The bag found a home in one of the pockets in Marina’s pants, her fingers nimble on the zipper-pull as she sealed it away. “Are we ready?”

Owe smiled at her as he reached to tug the zipper of her motorcycle jacket all the way up to her chin. His thumb brushed the lower curve of her jaw as he pulled away. “Whenever you are.”

“Then let’s get this done.”

He handed her the backpack that held their gear, helping her pull it over her shoulders and fasten the straps across her chest. Next, he straddled the seat and offered her a hand so she could climb on behind him. She pulled on the helmet he offered, fastening the strap under her chin before scooting closer to wrap her arms around his waist.

“You ready?” he called back over his shoulder. She tapped her helmet against his back in a gentle answer. “Hold on!”

Her fingers tightened against his stomach as the motorcycle roared to life, breath catching in her throat as the machine roared away from the motel and into traffic. Riding Owen’s motorcycle with him gave her an exhilarating and terrifying thrill. Part of her, buried deep in her heart, hoped another opportunity would surface in the future – hopefully without requiring bloodshed next time. Cuddling closer, she let her eyes slip closed, knowing he would keep her safe. No matter what, Lucky would never let anything happen to her. Sitting on the back of his bike could be counted as one of the safest places in the world.

Which . . . she should probably think about a little more at some point, especially given how few places she considered truly safe.

Owen stopped the bike about a mile away from their target. Letting Marina climb free, he pushed the vehicle off the road and into the shrubs lining the street. That camouflage wouldn’t hold up against an intense search, but they wouldn’t be long and the average citizen didn’t usually take the time to really scan their surroundings. 

A small tremor went through her hands as she took off her helmet, handing it to Owen so he could stash it with her backpack beside the motorcycle. She offered him a quick smile as she adjusted her leather gloves. “It is okay to be excited about this kill?”

“More than,” he promised as he pulled a black beanie over his blond hair. “The _Gadyuka_ anxious to come out and play?”

“You have no idea.” Her voice purred with a hint of expectation and she spotted something flicker in his eyes even as his smile shifted into a smirk. Making a mental note to consider it later, she offered a sly wink. “Shall we?”

“After you.”

Minutes later, she found herself face to face with the man responsible for some of the worst nightmares suffered by the Grimm family. Marina herself, Betty, and all five of the boys who escaped from Hoover still bore the scars caused by the shadow cast by Frank Cahill. What had she expected to feel when confronting this man? Vindicated? Relieved? Maybe even vicious? Thirty plus years of fear and hatred surely earned her that much.

So why did she feel so hollow?

Then again . . . the look on his face as he gaped at her almost made everything worth it.

“Hello, Doctor Cahill,” she greeted, drawing out the words in a lazy tone as she twirled her knife around one finger. “You look like you’ve seen a ghost.”

“Mary Peters.” The name came out in a whisper, his tone one of disbelief and shock, as Owen shoved the man into a chair before leveling a gun at his head. “It can’t be.”

“Who the hell is Mary Peters?” she smirked, a quiet sneer in the question. She tilted her head in a mock show of innocence before cocking an eyebrow as her gaze shifted to Owen. “Do you know a Mary Peters, _Medved_?”

“Can’t say that I do, Boss Lady."

The calm, cool reply seemed to make Cahill twitchy . . . or maybe it was the steady aim of the weapon aimed at him. Either way, she watched as he shifted before his face hardened. “You bitch!”

“So rude,” she scolded, tapping her knife against her thigh. “You could be seeing things – I hear age can cause that.”

“You betrayed us!”

“Allow me to introduce myself,” Marina smiled or, more accurately, bared her teeth. “I’m called _Gadyuka_.”

“What do you want?” Cahill demanded. 

“Me?” She rolled her shoulders in a lazy shrug. “Nothing much.” Her eyes glittered with the emotions rolling through her. “But Project One sends his condolences on the circumstances of your death.” Granted, most of Will’s sympathy had to do with the necessity of blood on their hands – hers and Lucky’s – but it sounded good.

Fear shot through those hate-filled eyes. “You can’t kill me.”

“I think you’ll find she can,” Owen corrected, his voice still detached, impassive, as if discussing the color of the walls.

“And won’t that be fun?” she prompted, a little sneer in her tone.

When renewed terror leeched the color from his skin, she couldn’t deny the joy _Gadyuka_ found in the sight – no matter what else she might feel.

A few hours later she stood at a distance and watched the house of a monster burn. Owen came to stand at her shoulder, his hands in the pockets of his bomber jacket. “Feel better?”

“No.” One corner of her lips twitched as she gave him the honest reply. “But it’s a start.” Turning to fully face him, she pushed herself up to press a warm kiss to the corner of his mouth. The action happened without thought and Marina forced herself to ignore the twist in her stomach at the normality of it. Could anything really be ‘normal’ today? “Let’s go home.”

He pulled one of his hands out of a pocket to brush back one of her curls with calloused fingers. “As you wish.”

**Notes for the Chapter:**

> Okay, I'm pretty sure I see pitchforks. So . . . I'm gonna run. Like now. Bye! *runs away* 
> 
> Translations: 
> 
> Gadyuka - Russian - Viper (the call sign given to Marina Petrovka by the Red Room which created her; kind of like Barney, the _Gadyuka_ is a separate entity than Marina though - unlike Barney- the _Gadyuka_ is one hundred percent under Marina's control)  
> Hola - Spanish - Hello  
> Mamacita - Spanish - diminutive form of "Mama" (Cassian's term for his adoptive mother, Marina Petrovka)  
> vorishka - Russian - little thief (Marina's nickname for her adoptive son, Cassian Andor Grimm)   
> ropa vieja - Spanish - Cuban Braised beef, usually served shredded (Cassian's grandfather, Javier Suarez, was Cuban, and an excellent cook; Cuban food was a staple of Cassian's growing up years after he came to live with his grandparents, until his grandfather died.)   
> fricasé de pollo - Spanish - Cuban Chicken Stew  
> Flan - Spanish - a Cuban dessert   
> Medved - Russian - Bear (Owen Elliot's SHIELD call sign)


	3. Killing Cahill Cast List

**Summary for the Chapter:**

> The cast of Killing Cahill

[ ](https://imgur.com/nY2ULLg)

[ ](https://imgur.com/ZwDgTXR)

Jeremy Renner as William Michael Grimm (Will Brandt)

[ ](https://imgur.com/nRv07LN)

Evangeline Lilly as Marina Ivanova Petrovka

[ ](https://imgur.com/TmHlkwI)

Devon Sawa as Owen Matthew Elliot

[](https://imgur.com/tICs2TQ)

Diego Luna as Cassian Jeron Grimm (Cassian Andor)

[ ](https://imgur.com/4sUFTI6)

Christopher Eccleston as Doctor Frank Cahill


End file.
